Complex compounds of a definite composition containing, as one or more ligands, the trisodium salt of triphenylphosphane trisulfonated in the meta position, of the chemical formula P(C.sub.6 H.sub.4 -m-SO.sub.3 Na).sub.3, are hardly known. In DE No. 2,700,904 C2, Example 12, the reaction of bis(1,5-cyclooctadiene)nickel with the trisodium salt of tris(m-sulfophenyl)phosphane (hereinafter called TPPTS) is described. A red compound is obtained which is recovered from its aqueous solution as a solid substance by evaporation in vacuo. According to the authors, this compound is supposed to be the tetrakis(trisodium) salt of tetrakis[(m-sulfophenyl)phosphane]nickel(0).
The same publication also contains general information about the preparation of TPPTS complex compounds of iron and palladium. Thus, water-soluble compounds or those compounds which go into solution under the reaction conditions are to be reacted with aqueous TPPTS solution in the presence of a reducing agent. Examples of suitable reducing agents are Na[BH.sub.4 ], K[BH.sub.4 ], zinc powder, magnesium, and borohydrides. Neither the preparation process nor individual compounds are described in more detail by means of examples or even characterized.
Complex compounds containing TPPTS as ligands, the exact composition of which is not known, are formed in various reactions from metals or metal compounds, TPPTS and, if appropriate, further ligands. Thus, rhodium complexes containing TPPTS ligands have achieved particular importance recently as components of catalyst systems which are used in the hydroformylation of olefins. Compared with other catalysts used for the same reaction, they have the advantage of being soluble in water; hence, the hydroformylation can be carried out in a heterogeneous medium comprising an aqueous and an organic phase (two-phase system), as a result of which the reaction product can be separated from the water-soluble catalyst by simple phase separation. Moreover, this procedure ensures that the valuable noble metal catalyst can be recovered almost without loss or be recycled into the synthesis step. Such a process is described, for example, in DE No. 2,627,354 B2.
The addition reaction of hydrogen cyanide with unsaturated organic compounds can also be carried out in the presence of a compound of zero-valent nickel or iron or palladium in a reduced oxidation state and an aqueous solution of a sulfonated triphenylphosphane, in particular an aqueous solution of TPPTS, as catalyst. This procedure is also described in DE No. 2,700,904 C2. Instead of the components nickel salt and TPPTS solution, it is also possible to use a specially prepared complex compound as the catalyst, to which the formula Ni(TPPTS).sub.4 is assigned.